The feasibility of using an auditory cue to elicit anticipatory postural adjustments for a posterior perturbation.

When humans are exposed to a predictable external perturbation, they usually generate anticipatory postural adjustments (APAs), which reduce the effect of potential body disturbance. However, when an external perturbation comes from behind and as such unpredicted, no APAs are generated, which challenges postural control. The aim of this study was to examine whether humans exposed to unpredictable perturbations could generate APAs using an auditory cue. Ten young adults were exposed to external perturbations hitting their shoulders from behind with or without an auditory cue prior to the physical impact. Electromyography (EMG) activities of eight trunk and leg muscles and center-of-pressure (COP) displacements were recorded and analyzed during the anticipatory and compensatory phases of postural control. Outcome measures included the latencies and integrals of muscle activities, COP displacements, and indices of co-contraction and reciprocal activation of muscles. The results showed that young adults were able to rely on an auditory cue to generate APAs prior to external perturbations coming from behind, and they demonstrated stronger APAs with training. Moreover, they utilized co-contraction of ventral and dorsal muscles as their APA response. The outcome provides a foundation for future studies aiming at using auditory cues to facilitate the generation of APAs and improve postural control in people with impaired balance while exposed to perturbations.

Older adults can rely on an auditory cue to generate anticipatory postural adjustments prior to an external perturbation.

To minimize the potential postural disturbance induced by predictable external perturbations, humans generate anticipatory postural adjustments (APAs) using visual information about a perturbation. However, it is unknown whether older adults can generate APAs relying on auditory information. Ten older adults received external perturbations (a) with visual information but no auditory information available, (b) without neither visual nor auditory information, (c) with both visual and auditory information available, and (d) participated in training with only auditory information available. In addition, they were tested again after 1 week of washout period. Electromyography activities of eight leg and trunk muscles and ground reaction forces were recorded and analyzed during the anticipatory and compensatory phases. Outcome measures included the latencies and integrals of muscle activities, and center-of-pressure displacements. After a short period of training, participants were able to rely on the auditory cue only to generate APAs close to that when the visual information was available. In addition, after 1 week of washout period, they were able to partially retain the skill to rely on auditory cues to generate APAs. The outcome provides a foundation for future studies focusing on utilizing auditory cues to optimize postural control in individuals who have balance or vision deficit.

The effect of the predictability of perturbation magnitudes in older adults with mild cognitive impairment.

Balance impairment is common in older adults with mild cognitive impairment (MCI). The ability to predict the magnitude of the body disturbance is essential to balance maintenance. The purpose of the study was to investigate the effect of the predictability of the perturbation magnitudes on anticipatory (APAs) and compensatory (CPAs) postural adjustments in older adults with MCI and healthy older adults. Fifteen individuals with MCI and fourteen age-matched control participants stood on the force platform and received the pendulum perturbations of small or large magnitudes applied to their upper body. Electromyographic activity of eight leg and trunk muscles and displacements of the center of pressure (COP) were recorded and analyzed during the APA and CPA phases of postural control. Individuals with MCI demonstrated smaller APAs in the conditions of the perturbation of unpredictable magnitude and required more trials to optimize their postural adjustments, as compared to healthy older adults. Moreover, individuals with MCI had reduced postural stability in the conditions of unpredictable magnitude of the perturbation. The findings suggest that cognitive decline adversely affects the ability to predict the magnitude of the perturbations.

Effect of predictability of the magnitude of a perturbation on anticipatory and compensatory postural adjustments.

Balance maintenance in response to a perturbation could be affected by the predictability of the magnitude of the body disturbance. We investigated anticipatory (APAs) and compensatory (CPAs) postural adjustments in response to perturbations of predictable and unpredictable magnitudes. Twenty young adults received series of perturbations of small or large magnitudes the order of which was varied. Electromyographic activity of six leg and trunk muscles and displacements of the center-of-pressure (COP) were recorded. The muscle onset time, integrals of muscle activity, and COP displacements in the anterior-posterior direction were analyzed during the APA and CPA phases. The results indicated that when the participants were exposed to the repeated perturbation magnitude, it became predictable and they generated APAs more precisely according to the magnitudes of the perturbation. Moreover, when the magnitude of perturbation changed unpredictably, the participants overestimated or underestimated the magnitudes of the perturbation, as they generated APAs based on their prior experience of dealing with the perturbation. The optimal adjustment of APAs occurred after five trials of repeated perturbations. The findings imply that the process of APAs and CPAs generation depends on the accuracy of the predictability of perturbation magnitudes.

The role of an auditory cue in generating anticipatory postural adjustments in response to an external perturbation.

Anticipatory postural adjustments (APAs) are usually generated to minimize the potential postural disturbance induced by predictable external perturbations. Visual information about a perturbation is important for the generation of APAs, but whether people can rely on auditory information to generate APAs is unknown. The aim of this study was to investigate the role of an auditory cue in generating APAs when visual information is not available. Fifteen young adults participated in the study. They received external perturbations a) with visual information but no auditory information available, b) without neither visual nor auditory information, c) with both visual and auditory information available, and d) with only auditory information available. Electromyography (EMG) activities of eight leg and trunk muscles and displacements of the center-of-pressure (COP) were recorded and analyzed during the anticipatory and compensatory (CPAs) phases. Outcome measures included the latencies and integrals of muscle activities, COP displacements, and indices of co-contraction and reciprocal activation of muscles. The results showed that after a short training, participants were able to rely only on the auditory cue to generate APAs comparable to that when the visual information was available. In addition, a training effect was found such that the participants demonstrated stronger APAs and less demands for CPAs through the training trials. The outcome provides a foundation for future studies focusing on the utilization of auditory cues for postural control in older adults and individuals who have vision deficit.

The Role of Predictability of Perturbation in Control of Posture: A Scoping Review.

Efficient maintenance of posture depends on the ability of humans to predict consequences of a perturbation applied to their body. The purpose of this scoping review was to map the literature on the role of predictability of a body perturbation in control of posture. A comprehensive search of MEDLINE, EMBASE, and CINAHL databases was conducted. Inclusion criteria were studies of adults participating in experiments involving body perturbations, reported outcomes of posture and balance control, and studies published in English. Sixty-three studies were selected. The reviewed information resources included the availability of sensory information and the exposure to perturbations in different sequences of perturbation magnitudes or directions. This review revealed that people use explicit and implicit information resources for the prediction of perturbations. Explicit information consists of sensory information related to perturbation properties and timing, whereas implicit information involves learning from repetitive exposures to perturbations of the same properties.

The Effect of Predictability of the Perturbation Magnitude on Anticipatory and Compensatory Postural Adjustments during a Bimanual Load-Lifting Task.

Background: To minimize the potential postural disturbance induced by external or self-initiated perturbations, humans generate anticipatory postural adjustments based on their perceived consequences of the body disturbance. Lifting is a common activity that induces a self-initiated perturbation that can compromise balance control. Aim: To assess anticipatory (APAs) and compensatory (CPAs) postural adjustments generated in response to a self-initiated perturbation induced by lifting objects of uncertain mass. Methods: Ten young adults lifted the tray with either light or heavy object placed in it. Electromyographic activity of eight trunk and leg muscles, and center-of-pressure (COP) displacements were recorded and analyzed during the APAs and CPAs phases. Results: When the object mass changed unpredictably, the participants generated APAs based on the most recent experience of lifting and needed three trials of lifting to generate optimal APAs and CPAs. Conclusions: Young adults were able to predict the perturbation magnitude during self-initiated perturbations induced by lifting objects. The outcome provides a foundation for future studies focusing on the role of predictability of perturbation consequences in postural control of older adults and individuals with balance deficit.

Older adults utilize less efficient postural adaptations when they are uncertain about the magnitude of a perturbation.

People frequently experience perturbations while standing or walking in crowded areas or when interacting with external objects. Balance maintenance in response to a perturbation is affected by the predictability of the magnitude of a body disturbance. The aim of this quasi-experimental study was to investigate the role of aging in maintenance of standing balance in response to perturbations of varying magnitudes. Twelve older adults and twelve young adults received a series of frontal perturbations of small or large magnitudes induced to their upper body by a pendulum impact while standing. The perturbation sequence included 10 trials of small, 15 trials of large, and 10 more trials of small magnitudes. The participants were exposed to either repetitive perturbations of known (predictable) magnitude or perturbations of unknown (unpredictable) magnitude as they were not told which of the perturbation magnitude (small, large) to expect. Electromyographic activity of six leg and trunk muscles and displacements of the center of pressure were recorded and analyzed during anticipatory (APAs) and compensatory (CPAs) phases of postural control. When exposed to both, repetitive perturbations of known magnitude and perturbations of unpredictable magnitude, older adults, compared to young adults, demonstrated delayed and smaller anticipatory and compensatory postural adaptations. Older adults also required more trials to modify postural adjustments, as compared to young adults. The findings imply that the ability to predict magnitudes of frontal perturbations is declined in older adults.

The role of predictability of the magnitude of a perturbation in control of vertical posture when catching an object.

The predictability of perturbation magnitude plays an important role in control of standing posture. The aim of the study was to examine anticipatory (APAs) and compensatory (CPAs) postural adjustments in response to catching objects of uncertain mass. Twenty adults caught the same object with either light or heavy weight placed in it. Electromyographic activity of eight trunk and leg muscles, displacements of the center of pressure, and angular displacement of the shoulder joint were recorded and analyzed during the APAs and CPAs intervals. When the subjects experienced repeated catching of the object with the same weight, they estimated the object mass beforehand and generated APAs more precisely. When the object mass changed unpredictably, they generated APAs based on the most recent catch and needed four to six trials to optimize APAs and CPAs. The muscle co-contraction was a primary pattern for catching the object of uncertain mass. The results of the study suggest that catching the object of uncertain mass is a challenging task that involves co-contraction of postural muscles to maintain balance.

Integrating participatory ergonomic management in non-weight-bearing exercise and progressive resistance exercise on self-care and functional ability in aged farmers with knee osteoarthritis: a clustered randomized controlled trial.

BACKGROUND: Ergonomic hazards are the most important cause of knee osteoarthritis (OA) in aged para rubber farmers. Ergonomic management comprising improvement of working conditions and muscle-strengthening exercise has been well documented in terms of workers' health benefit. However, those interventions were not adequate to sustain the advantage. Few studies have demonstrated the effect of integrating participatory ergonomic management (PEM) in non-weight-bearing exercise (NWE) and progressive resistance exercise (PRE), and none has focused on aged para rubber farmers with knee OA. PURPOSE: This study investigated the effect of PEM-NWE, PEM-PRE, and standard treatment (ST) on self-care and functional ability in the aged population. MATERIALS AND METHODS: A single-blinded, clustered randomized controlled trial was carried out. Participants (n=75) from three different communities in southern Thailand were randomly assigned to PEM-NWE, PEM-PRE, and ST. Self-care and functional ability (pain, stiffness, and physical function) were examined at baseline (B), during the intervention at Week 5 (W5), and after its completion at Week 9 (W9). Mean comparison of those outcomes over time was made using Generalized Linear Mixed Models (GLMMs). RESULTS: Compared to the standard treatment, the means of both groups, PEM-NWE and PEM-PRE, were significantly increased in self-care and functional ability. However, no significant difference between PEM-NWE and PEM-PRE was found. CONCLUSION: Either or both interventions should be incorporated into nursing practice in order to promote occupational health and enhance quality of work life for Thai aged farmers. Further study on their cost-effectiveness is highly recommended.

Results From Thailand's 2016 Report Card on Physical Activity for Children and Youth.

BACKGROUND: Physical activity (PA) is recognized as one of the core modifiable risk factors of noncommunicable diseases. However, little is known about PA in the Thai population, particularly in children. The report card (RC) project provided Thailand with an opportunity to assess PA behaviors in children. This paper summarizes the methodology, grading process, and the final grades of the Thai RC. METHODS: A school-based survey was conducted to collect data from a nationally representative sample of children aged 6 to 17 years. Survey results provided the primary source for the RC. Nine indicators were graded using the Global Matrix 2.0 framework. Grading was undertaken by a national committee comprising experts from key stakeholders. RESULTS: Grades ranged from F to B. Overall PA and Sedentary Behaviors both received the grade D-. Organized Sport Participation scored a C. Active Play scored the grade F. Active Transport and support from Family and Peers were both graded B. School, Community, and Government indicators were scored C. CONCLUSIONS: In Thai children, participation in PA and active play is very low; conversely, sedentary behaviors are high. These first data on patterns of activity for the Thailand RC will serve to guide national actions and advocacy aimed at increasing PA in children.